DESCRIPTION

The explain_strtoull_or_die function is used to call the
strtoull(3) system call. On failure an explanation will be printed
to stderr, obtained from the explain_strtoull(3) function,
and then the process terminates by calling exit(EXIT_FAILURE).

The explain_strtoull_on_error function is used to call the
strtoull(3) system call. On failure an explanation will be printed
to stderr, obtained from the explain_strtoull(3) function,
but still returns to the caller.